[Aleksandergreg]

• printf '%s\n' a b c printed only a. The format now repeats, and %d and widths work.
• tail -n +2 printed the last 2 lines instead of starting at line 2. head -n -1 works now too.
• tr '[:lower:]' '[:upper:]' garbled text instead of uppercasing it.
• grep 'ERROR|WARN' found nothing, and sed 's/(x)/\1/' and s/x/[&]/ didn't work. Both now use standard Linux regex rules, with -E for the extended form.
• sort -n put 100ms before 9ms.
• wc file printed only the line count.
• [!x]* globs matched the opposite of what they should.
• rm deleted directories without -r.
• touch -a f created a file named -a; that and cat -n, mv -f and similar now say "unknown option" instead.

Game and CLI fixes (done by a helper agent in a separate copy, then merged and reviewed by me):

• Moving to a Docker mission from inside a game when Docker isn't running used to end the whole session; now the player stays in the current mission.
• After Docker missions, the "continue with…" hints pointed players to the Linux missions instead.
• Hints the player already paid for can now be re-read.
• A corrupt profile file now names its path, and doctor keeps running its other checks.
• help, man, clear and history no longer count toward the "Command Collector" achievement.
• Flag errors no longer print twice, and play 4 --once now works.
• In-game list --campaign now finds Docker worlds too.

Smaller fixes:

• Every mission now has a home directory; most were missing it, so plain cd failed.
• A paragraph was duplicated in the README.
• Several docs had wrong text: the world naming, and saying hints cost "bonus XP" when they actually reduce the mission's reward.